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A034833 a(n) = n-th sept-factorial number divided by 6. 8
1, 13, 260, 7020, 238680, 9785880, 469722240, 25834723200, 1601752838400, 110520945849600, 8399591884569600, 697166126419276800, 62744951377734912000, 6086260283640286464000, 632971069498589792256000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..339

Index entries for sequences related to factorial numbers

FORMULA

a(n) = A049209(n)/6;

a(n) = (7*n-1)(!^7)/6;

a(n) = (1/6)*Product_{j=1..n} (7*j-1);

a(n) = (1/6)*(7*n)! / (7^n * n! * A045754(n) * 2*A034829(n) * 3*A034830(n) * 4*A034831(n) * 5*A034832(n)).

E.g.f.: (-1 + (1-7*x)^(-6/7))/6.

MATHEMATICA

FoldList[Times, 1, Rest[7*Range[20]-1]] (* Harvey P. Dale, Dec 15 2014 *)

PROG

(PARI) x='x+('x^30); Vec(serlaplace((-1 + (1-7*x)^(-6/7))/6)) \\ G. C. Greubel, Feb 22 2018

(MAGMA) [(&*[(7*k-1): k in [1..n]])/6: n in [1..30]]; // G. C. Greubel, Feb 24 2018

CROSSREFS

Cf. A049209, A045754, A034829, A034830, A034831, A034832, A034834.

Sequence in context: A321849 A034242 A142811 * A101004 A142931 A142262

Adjacent sequences:  A034830 A034831 A034832 * A034834 A034835 A034836

KEYWORD

easy,nonn

AUTHOR

Wolfdieter Lang

STATUS

approved

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Last modified February 20 13:20 EST 2020. Contains 332077 sequences. (Running on oeis4.)